This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A350427 #5 Jan 06 2022 08:17:10 %S A350427 1,3,7,12,16,20,27,34,39,44,51,57,63 %N A350427 a(n) is the maximum number of key comparisons required to sort n records with distinct keys using a modified heapsort (Algorithm H in Don Knuth's TAOCP Vol. 3, answer to exercise 18). %C A350427 There are two places in R. W. Floyd's modified algorithm where the keys are compared. The first is in step H4 [Find larger child.] and the second in step H9' [Does K fit?]. The sequence shows the maxima of the counts of these comparisons, determined over all n! possible orders of the records. %D A350427 D. E. Knuth, The Art of Computer Programming Second Edition. Vol. 3, Sorting and Searching. Chapter 5.2.3 Sorting by Selection, Pages 145, 156 and 642. Addison-Wesley, Reading, MA, 1998. %Y A350427 Cf. A350426, A350428. %Y A350427 A350569 contains a table with the maximum and average number of comparisons for the original algorithm and for its modified version. %K A350427 nonn,more %O A350427 2,2 %A A350427 _Hugo Pfoertner_, Jan 05 2022